Interesting and lengthy adventure through seven completely different stages, with seven completely different bosses, some of these stages and bosses being based on other games. The difficulty curve is very solid, with the beginning being a fair challenge, probably doable by anyone with the right amount of effort, and getting tougher and tougher as you progress. The platforming is quite interesting, mixing tricky gimmicks, traps and, later on, needle jumps. Some saves are really boring (Mainly when there's a randomly placed needle jump involved), but the platforming is mostly enjoyable. The bosses are also really well-made, although their HP is a bit too high (Destination takes around 5 minutes to beat).
It's definitely worth checking regardless of your skill level: This game is great from the beginning to the end. Would recommend.